Benefits of Moderate Exercise Outweigh Air Pollution Harm

A University of Cambridge study suggests that while the effects of air pollution are staggering (the airborne scourge contributes to 40,000 deaths each year in the United Kingdom alone), the health benefits of moderate exercises like walking and bicycling "outweigh" the harm that polluted air can wreak on our overall health.

But Dr Marko Tainio, the lead author of the study published in Preventive Medicine, also noted that "a small minority of workers in the most polluted cities, such as bike messengers, may be exposed to levels of air pollution high enough to cancel out the health benefits of physical activity."

According to the World Health Organization, the average air pollution level for cities around the globe is 22 micrograms per cubic meter. In London, that level was 16 micrograms per cubic meter in 2011. Delhi, with the world's highest annual average concentration of small airborne particles, measures around 150 micrograms per cubic meter. In the U.S., roughly a third of cities currently measure above the WHO standard of 10 micrograms of fine particulate matter per cubic meter.